Display device
A display device includes a signal processor, a display component, a substrate, and a conductive housing. The signal processor includes an oscillator that outputs oscillation signal, the signal processor processing signal whose frequency is higher than a specific threshold. The display component displays video. The substrate has a ground component, the signal processor being disposed on the substrate. The conductive housing is connected to a first site of the ground component and to a second site that is different from the first site. The first site and the second site are disposed at positions where a first area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the first site overlaps at least part of a second area of the housing that is a multiple of ¼ wavelength of the oscillation signal away from the second site.
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This is a continuation application of U.S. patent application Ser. No. 15/690,981 filed on Aug. 30, 2017, which claims priority to Japanese Patent Application Nos. 2016-171954 filed on Sep. 2, 2016 and 2016-171958 filed on Sep. 2, 2016. The entire disclosures of U.S. patent application Ser. No. 15/690,981 and Japanese Patent Application Nos. 2016-171954 and 2016-171958 are hereby incorporated herein by reference.
BACKGROUND Field of the InventionThe present invention relates to a display device comprising a tuner device that receives television broadcasts, etc., and more particularly relates to a technique for reducing unnecessary radiation (EMI: electromagnetic interference) from a metal housing of the tuner device.
Background InformationJapanese Laid-Open Patent Application Publication No. 2015-109551 (Patent Literature 1) discloses a conventional tuner in a display device that reduces unnecessary radiation, which employs a configuration in which the length, width, depth, and diagonal (the linear distance between two vertices that are the farthest apart) dimensions of a shield case (metal housing) that houses a tuner IC are all set to be shorter than the half wavelength of the highest frequency out of the source oscillation frequencies of the oscillator of the housed tuner IC.
International Publication No. WO 2015/119151 A1 (Patent Literature 2) discloses a configuration in which the ground of a circuit board is connected by a plurality of conductor posts to the center part of the upper face of a conductor shield (housing) in which electronic parts are sealed and the distance between the conductor posts is equal to or smaller than ¼ the wavelength of the highest frequency used, so as to reduce unnecessary radiation attributable to resonance of the conductor shield.
Japanese Laid-Open Patent Application Publication No. 2007-299099 (Patent Literature 3) discloses a configuration in which conductive posts (grounding posts) that connect a metal housing to a printed board are disposed evenly in the interior of the housing, or as evenly as possible along the ends of the housing, and the spacing of these grounding posts is set to be no more than one-fourth the wavelength of electromagnetic waves corresponding to a frequency that is not apt to generate EMI.
SUMMARYHowever, although the tuner ICs installed in tuner devices today have become smaller and more integrated, there is a limit to how small the capacitors and inductors housed in a metal housing can be made, so there is also a limit to the size of the metal housing in the length, width, depth, diagonal, and other such dimensions. Meanwhile, as the capacitors and so forth built into an IC become smaller, a high oscillation frequency, such as from a few gigahertz to a few dozen gigahertz, is used for the voltage control oscillator (VCO) housed in the metal housing, and because of this, the half value of the wavelength λ (λ/2) of the signal with the highest oscillation frequency is extremely low. Accordingly, even though the technique in the above-mentioned Patent Literature 1 is to set the length, width, depth, and diagonal dimensions of the metal housing to be no more than half the wavelength of the signal with the highest oscillation frequency (λ/2), in actual practice this is quite difficult, and as a result, a range or site occurs in which the impedance is high in the metal housing, and a large amount of unnecessary radiation is produced from this range or site.
Furthermore, with the technique in Patent Literature 1, even if we assume that the diagonal size of the housing (the linear distance between two vertices that are the farthest apart), such as the linear distance between the upper-left corner of the front face of a tetragonal housing and the upper-right corner of the rear face that is opposite this front face, can be set to no more than half the wavelength (λ/2) of the signal with the highest oscillation frequency of the VCO, if the lower-left corner of the front face of the housing and the lower-right corner of the rear face are grounded, the conductor shield will resonate in a size that is the total of the diagonal length of the upper face of the tetragonal housing and two times the height of this housing, so this total size greatly exceeds half the wavelength of the signal with the highest oscillation frequency (λ/2), and once again a large amount of unnecessary radiation ends up being produced.
Also, with the technique in the above-mentioned Patent Literature 2 and the technique in the above-mentioned Patent Literature 3, since grounding posts are disposed as evenly as possible along the end or in the interior of the housing, the large number of grounding posts is a drawback in that the configuration is more complicated and the cost is higher.
One object of the present disclosure is to reduce the number of grounding sites while being able to achieve low impedance everywhere on a housing, and effectively reduce unnecessary radiation, even if the length, width, and other such dimensions of the housing are greater than the half wavelength of the highest oscillation frequency of the oscillator (λ/2), in a tuner device of a display device in which a housing that houses an oscillator in its interior is disposed on a substrate.
To achieve the stated object, with the present disclosure, since unnecessary radiation naturally occurs at places of high impedance on the housing, using the grounded sites of the housing as the reference impedance, unnecessary radiation is reduced by providing grounding sites that forcibly lower the impedance at these housing sites where the impedance is high.
In view of the state of the known technology and in accordance with an aspect of the present invention, a display device includes a signal processor, a display component, a substrate, and a conductive housing. The signal processor includes an oscillator that outputs oscillation signal, the signal processor processing signal whose frequency is higher than a specific threshold. The display component displays video. The substrate has a ground component, the signal processor being disposed on the substrate. The conductive housing is connected to a first site of the ground component and to a second site that is different from the first site. The first site and the second site are disposed at positions where a first area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the first site overlaps at least part of a second area of the housing that is a multiple of ¼ wavelength of the oscillation signal away from the second site.
Referring now to the attached drawings which form a part of this original disclosure:
Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the art from this disclosure that the following descriptions of the embodiments are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
First EmbodimentIn the tuner IC 10 in
The RF amplifier 1 amplifies a received signal having an RF frequency of 90 to 767 MHz, which is the frequency of ground wave television broadcasts in Japan, for example, and the interstage filter 2 limits the band of the amplified signal. The VCO/PLL circuit (oscillator) 3 changes the oscillation frequency of the oscillation signal outputted by a built-in local oscillator depending on the tuning voltage of the PLL circuit, thereby generating a frequency range of at least 2 GHz, such as an oscillation frequency of 6 to 8 GHz. The 1/N circuit 4 converts the oscillation frequency generated by the VCO/PLL circuit 3 to a 1/N multiple (such as 6 to 133), and thereby gives a local oscillation frequency of 96.5 to 770.5 MHz, for example. The mixer 5 converts the frequency of the received signal by mixing the received signal with an RF frequency from the interstage filter 2 with the local oscillation frequency from the 1/N circuit 4. The detector 6 outputs the differential voltage of the differential outputs from the mixer 5. The interstage filter 7 limits the band of the differential output signal of the mixer 5 that has gone through the detector 6. The IF amplifier 8 amplifies the received signal that has undergone frequency conversion and band limitation, and outputs a signal with an IF frequency of 3.5 MHz, for example. The AGC circuit 9 generates gain control signals RF AGC and IF AGC that control the degree of amplification of the RF amplifier 1 and the IF amplifier 8 on the basis of the differential voltage between the differential outputs of the mixer 5 detected by the detector 6.
As shown in
The tuner IC 10 forms a signal processor that processes signals of a frequency higher than a specific threshold. In this embodiment, a signal processor is formed by the tuner IC 10, so when the bandwidth of the RF signal that is received is from 50 MHz to 3.2 GHz, the above-mentioned specific threshold is 50 MHz.
Also, while the signal processor is formed by the tuner IC 10 in this embodiment, the present invention is not limited to or by this, and the signal processor may instead be formed by WiFi, Bluetooth (registered trademark), or another such wireless communication component that sends and receives information signals. In this case, the bandwidth of the RF signal of the WiFi, Bluetooth (registered trademark), or other such wireless communication component is from 2.4 to 2.5 GHz or 5 to 6 GHz, so the above-mentioned specific threshold is approximately 2.4 GHz, and since the frequency is the same as that of the oscillation signal of the tuner in the case of an oscillation signal in wireless communication, the specific threshold is approximately 2 GHz.
As shown in
As shown in
The housing 22 that houses the tuner IC 10, etc., and the main board 20 on which this housing 22 is disposed form a tuner device in the television broadcast reception circuit of this embodiment.
With the above television broadcast reception circuit, the housing 22 is disposed on the main board 20, but also disposed are a microcomputer for performing processing to demodulate television broadcast waves, etc., a memory, power supply parts, noise suppression parts for preventing the admixture of noise into the numerous signal patterns formed on the main board 20, an external interface for connecting television cables and the like, and so on.
Dimensions of Housing
An example of the dimensions of the housing 22, taking into account the size of the quartz oscillator 15 or the tuner IC 10 housed therein, or the capacitor, inductor, and other such chip parts 16, is a length L of 17 mm, a width W of 20 mm, a height H of 10 mm, and a diagonal length D of 26.24 mm, at the very smallest. Since the frequency of the oscillation signal generated by the VCO/PLL circuit 3 of the tuner IC 10 is 6 to 8 GHz, the shortest length at which the effect of shielding against unnecessary radiation in the housing 22 will completely disappear, that is, the half value (λ/2) of the wavelength λ at the highest oscillation frequency of the oscillation signal (8 GHz), is 18.75 mm. Therefore, in the dimensions of the housing 22, since the width W of 20 mm and the diagonal length D of 26.24 mm exceed the above-mentioned half wavelength (λ/2), something needs to be done to reduce unnecessary radiation. Furthermore, given that the diameter of the F-type connector 23 is established by standard, when the housing 22 is grounded to the main board 20 at the two corners C1 and C2 shown in
Therefore, it is usually extremely difficult to specifically establish the grounding sites of the housing 22 so that unnecessary radiation can be reduced to below the standard over the entire variable range of the oscillation frequency at the VCO/PLL circuit 3.
Features of this EmbodimentThis embodiment makes use of a configuration in which unnecessary radiation can be easily, effectively, and reliably reduced even when any of the various dimensions of the housing 22 cannot be made less than the half wavelength (λ/2) at the highest oscillation frequency (8 GHz), as discussed above. This will be described in detail below.
Specification of First Grounding Sites
First of all, first grounding sites are specified arbitrarily. These first grounding sites will be described by using an example of when the number of grounding sites shown in
The housing 22 is formed in a tetragonal shape by working a single piece of sheet metal.
The main board 20, meanwhile, is configured as follows.
As shown in
As shown in
Meanwhile, at the two corners 22t and 22u of the housing 22 that are not grounded, just as with the corners 22r and 22s that are grounded, the legs 22i and 22j are inserted into the through-holes 20s of the main board 20, and in this state the through-holes 20s and the legs 22i and 22j are attached with the solder 25, thus fixing the two corners 22t and 22u of the housing 22 that are not grounded, to the lands 20f and 20h of the main board 20, but not connecting them to the grounding pattern 20c.
With the above configuration, in this embodiment, because of the configuration of the housing 22 shown in
Establishing High Impedance Range in Housing
As discussed above, the highest frequency of the oscillation signal at the VCO/PLL circuit 3 is 8 GHz, and when the wavelength λ shortens to about 40 mm, if the size of the housing 22 exceeds the half wavelength (λ/2), then impedance will be a distributed element (distributed constant) in the housing 22, which serves as the propagation path for the oscillation signal. With this distributed element circuit, a grounding site serves as the reference impedance, and a site that is an odd-numbered multiple of λ/4 away from this grounding site will be an open end, resulting in high impedance. When a plurality of grounding sites are provided, overlapping parts of sites that are an odd-numbered multiple of λ/4 away from these grounding sites will have the highest impedance.
More specifically, in the developed view of the housing 22 shown in
Therefore, in the developed view of
Reduction of Impedance in High Impedance Ranges of Housing
As discussed above, high impedance ranges occur in the housing 22, and the location and surface area of these high impedance ranges vary with the grounding sites of the housing 22. In this embodiment, a configuration is employed that reliably reduces the impedance of these high impedance ranges.
In
Therefore, in this embodiment, the range of particularly high impedance and/or the range of particularly high radiation directionality in the high impedance range B that occurred in a developed view of the housing 22 (see
Therefore, in this embodiment, since it is possible for the impedance in both of the high impedance ranges A and B caused by the two first grounding sites 22r and 22s to be lowered by a single second grounding site 22w, it is also possible to keep the number of second grounding sites that lower the impedance of high impedance ranges lower than the number of first grounding sites that cause those high impedance ranges.
Therefore, with this embodiment, there is no need to dispose grounding posts (grounding sites) as evenly as possible along the ends or the inside of the housing 22 as in the past, so the configuration of the housing 22 can be simpler and it can be produced at lower cost.
With this embodiment, a second grounding site was disposed at a point that was exactly an even-numbered multiple of ¼ the wavelength λ of the oscillation frequency away from the point of high impedance in this frequency, but the present invention is not limited to this, and the second grounding site need not be disposed exactly an even-numbered multiple of ¼ the wavelength λ away, as long as it is sufficiently close.
Usually, impedance can be kept low within a range of λ/20 from a grounding site, so the grounding sites are often designed at a spacing of λ/10 (the center between grounding sites is exactly λ/20 from the grounding sites) in housings and substrates with which there are no particular restrictions on cost or shape.
Because of this, it may be concluded that the effect of the present disclosure can be sufficiently obtained as long as the second grounding site is disposed at a point within 1/20 the wavelength λ from a distance that is an even-numbered multiple of ¼ the wavelength λ of the oscillation frequency away from a point of high impedance at this frequency.
For instance, in
Doing this allows the effect of the present disclosure to be sufficiently obtained even if there are restrictions on where the second grounding site can be disposed, for example.
Also, in
In
Therefore, again in this modification example, it is possible to lower the impedance in both of the high impedance ranges A and B caused by the two first grounding sites 22r and 22s, with just a single second grounding site 22x.
Second Modification ExampleIn this modification example, the configuration in
When the two second grounding sites 22w and 22x are both provided, it will be possible to lower the impedance of the high impedance ranges A and B over a wider range if, for example, one of the grounding sites (such as 22w) is disposed at a position that is separated by a half wavelength (λ/2) from near a position at the oscillation frequency of 6.8 GHz within the high impedance ranges A and B, and the other grounding site (such as 22x) is disposed at a position that is separated by a half wavelength (λ/2) from near a position at another oscillation frequency (such as 6.9 GHz) within the high impedance ranges A and B.
With the above embodiment and the above first and second modification examples, the second grounding sites 22w and 22x were disposed at a position that was half a wavelength (λ/2) (that is, two times λ/4) away in straight line distance in a developed view of the housing 22, but the present invention is not limited to this, and if the housing 22 is large in size in its length, width, etc., the high impedance ranges that occur in the housing can still be effectively reduced if these sites are disposed at a position that is separated by an even-numbered multiple of four or more times the λ/4 of the wavelength λ of the oscillation signal.
Furthermore, with the above embodiment and the above first and second modification examples, a case in which the first grounding sites were the two corners 22r and 22s was described, as shown in the examples in
Specific Configuration of Second Grounding Site
In
In
In
In this embodiment, the impedance is lowered in a range near the F-type connector 23 in a developed view of the housing 22.
As shown in
As shown in
Therefore, in this embodiment, a high impedance range F that occurs in the upper middle part of the rear face d of the housing 22 does remain, but the second grounding site 22z lowers the impedance over a wide range of the high impedance range E produced in the upper middle part of the front face b of the housing 22, so the unnecessary radiation from this range E can be reduced, and the unnecessary radiation that is generated in the RF cable 24 connected to the F-type connector 23 can be effectively reduced. As a result, the impedance distribution over the housing is less apt to be affected by variance in the state of the RF cable 24 (type, material, shape, etc.), and the effect is that less unnecessary radiation is caused by variance in the state of the signal cable.
Third EmbodimentIn
More specifically, in
As shown in
Since the metal line 35 is a point-to-point construction, in
Therefore, in this embodiment, even if the housing is relatively small in size, the second grounding site 22wo that is separated from the housing 22 will be able to reduce the impedance over a wide range of the high impedance range B of that housing 22.
Furthermore, with this configuration, as can be seen from
In the third embodiment, the second grounding site 22wo was disposed outside the housing 22, but in this modification example, the second grounding site is disposed in an area of the main board (specific area) located under the housing 22.
In
A specific example of this is shown in
The length of the wiring pattern 20m is determined as follows. In this modification example, since the wiring pattern 20m is disposed on the main board 20, the wavelength λ′ of the oscillation signal is shortened on the main board 20 by the dielectric constant er of the main board 20 to 1/(er1/2) the wavelength λ in a vacuum. For example, if the distance from the position of the high impedance range B of the housing 22 to the bottom edge k of the left face e of the housing 22 is 90% of the wavelength λ/2 in the air (two times λ/4), then a distance of 10% of ¼ times the wavelength λ′ at the dielectric constant er should be used for the line length of the wiring pattern 20m. More specifically, if we let the dielectric constant er of the main board 20 be 4, and the oscillation frequency f of the oscillation signal be 8 GHz, then the wavelength λ′ at the dielectric constant er is as follows.
λ′=(1/(er1/2))λ=(½)×(c/f)
c: speed of light=(½)×(3×108/(8×109))=0.01875 m=18.75 mm
Therefore, the line length can be calculated as 18.75×(¼)×0.1=0.46875 mm 0.5 mm
Therefore, in this modification example, since the second grounding site 22w1 is disposed in an area of the main board located under the housing 22, even if a microprocessor, a memory, or the like is disposed near the housing 22 on the outside, these devices will not get in the way, and the second grounding site 22w1 can be properly disposed at the accurate spacing of the length of the wiring pattern 20m from the housing 22.
In this modification example, the extension line Lo is formed by the wiring pattern 20m, and its shape is linear, but the wiring pattern 20m may instead be in the shape of an arc extending around the land 20; or in a shape that extends in an undulating form, or a through-hole formed in the main board 20 may be utilized to ground to the grounding pattern 20c on the rear face of the main board 20 and to extend the distance, etc.
Fourth EmbodimentA fourth embodiment of the present disclosure will now be described through reference to
In the first embodiment shown in
More specifically, in
Therefore, with this embodiment, when extension line L2 is a point-to-point construction, there is no reduction of the wavelength tied to dielectric constant, so the line length of the extension line L2 may be the actual length found by subtracting the distance between the high impedance point and the right corner 22s of the rear face d of the housing 22 from a length that is two times ¼ the wavelength λ (=λ/2) at the oscillation frequency (6.8 GHz) of the oscillation signal.
Modification Example of Extension LineMore specifically, an extension line L5 is made up of a wiring pattern 20q that extends from the ungrounded land 20g toward an area of the main board located under the housing 22 as shown in
With the above embodiment and the first and second modification examples, since the extension lines L2 to L5 make use of wiring patterns formed on the main board 20, there is no need for other members such as metal wires, and the extension lines L2 to L5 can be simply configured.
Therefore, in this fourth modification example, the distance between the corner of the housing 22 (land 20g) and the grounding site 22w′ can be adjusted merely by adjusting the length of the wire-shaped conductor L6 and the wiring pattern 20q.
Therefore, in this modification example, the distance between the corner of the housing 22 (land 20g) and the grounding site 22w′ can be adjusted merely by adjusting the length of the leaf spring-shaped conductor L7.
In all of the modification examples of the extension line L described above, the length of the extension line L can be freely increased or decreased, so the distance from the high impedance point P of the housing 22 to the grounding site 22w can be accurately set to an even-numbered multiple of ¼ the wavelength λ, regardless of the oscillation frequency range of the oscillation signal of the VCO/PLL circuit 3.
Fifth Modification ExampleA fifth modification example of the present disclosure will now be described through reference to
In the fourth embodiment (
More specifically, in this embodiment, in the developed view of the housing 22 in
In a developed view of the housing 22, the point P is the point nearest the right corner 22s of the rear face d among points of a distance that is three times ¼ the wavelength λ at the lowest frequency (in the drawing, 6 GHz) in the variable frequency range of the oscillation signal of the VCO/PLL circuit 3 from the left corner 22r of the front face b (points within the high impedance range B shown in
As already discussed, with a housing 22 in which the oscillation frequency of the oscillator is high and the impedance is distributed element manner, by using the grounding site of the left corner 22r of the front face b as a reference impedance, the impedance is higher than a predetermined specific impedance at the point P that is an odd-numbered multiple (three times) of λ/4 away from this grounding site in straight line distance in a developed view, but with this embodiment, since the impedance at the point P can be lowered to be less than a specific impedance, which is a site at a distance that is an odd-numbered multiple (one times) of ¼ the wavelength λ at the lowest frequency (6 GHz) of the oscillation signal away from the open site 22op of the housing 22 (the other end of the extension line L3), the impedance can be actively lowered in the range around the high impedance point P.
If the extension line L3 is a point-to-point construction, there will be no reduction in wavelength tied to dielectric constant. Therefore, the actual line length of the extension line L3 may be used in calculating the distance to the high impedance point P.
The configuration in which the other end of the extension line L3 is open can be the configuration shown in
A configuration in which the other end of the extension line L3 is open can also be applied to the already discussed configurations in
Therefore, in this embodiment, the impedance at the point P that is the high impedance range can be actively lowered by opening the other end of the extension line L3, so the occurrence of unnecessary radiation can be eliminated even more.
Sixth Embodiment Features of this EmbodimentThis embodiment makes use of a configuration in which unnecessary radiation can be easily, effectively, and reliably reduced even when any of the various dimensions of the housing 22 cannot be made less than the half wavelength (λ/2) at the highest oscillation frequency (8 GHz), as discussed above. This will be described in detail below.
Specification of Candidates of Grounding Sites
First of all, candidates of grounding sites are specified arbitrarily. These grounding sites will be described by using an example of when the number of grounding sites shown in
The housing 22 is formed in a tetragonal shape by working a single piece of sheet metal.
The main board 20, meanwhile, is configured as follows.
As shown in
As shown in
Meanwhile, at the two corners 22t and 22u of the housing 22 that are not grounded, just as with the corners 22r and 22s that are grounded, the legs 22i and 22j are inserted into the through-holes 20s of the main board 20, and in this state the through-holes 20s and the legs 22i and 22j are attached with the solder 25, thus fixing the two corners 22t and 22u of the housing 22 that are not grounded, to the lands 20f and 20h of the main board 20, but not connecting them to the grounding pattern 20c.
With the above configuration, in this embodiment, because of the configuration of the housing 22 shown in
Establishing High Impedance Range in Housing
As discussed above, the highest frequency of the oscillation signal at the VCO/PLL circuit 3 is 8 GHz, and when the wavelength λ shortens to about 40 mm, if the size of the housing 22 exceeds the half wavelength (λ/2), then impedance will be a distributed element in the housing 22, which serves as the propagation path for the oscillation signal. With this distributed element circuit, a grounding site serves as the reference impedance, and a site that is an odd-numbered multiple of λ/4 away from this grounding site will be an open end, resulting in high impedance. When a plurality of grounding sites are provided, overlapping parts of sites that are an odd-numbered multiple of λ/4 away from these grounding sites will have the highest impedance.
More specifically, in the developed view of the housing 22 shown in
Therefore, in the developed view of
Reducing High Impedance Range of Housing
As discussed above, high impedance ranges occur in the housing 22, and the location and surface area of these high impedance ranges vary with the grounding sites of the housing 22. In this embodiment, a configuration is employed that reliably reduces the size of these high impedance ranges. This will be described in specific terms below.
In this drawing, the high impedance range B (see
In this embodiment, as can be seen from
In
In this embodiment, in the developed view of the housing 22 in
The extension line L in this embodiment is a point-to-point construction, so wavelength contraction tied to dielectric constant does not occur. Therefore, the actual line length of the extension line L should be used in calculating the distance to the high impedance point P.
Therefore, with this embodiment, a high impedance range produced in the housing 22 will only be at the high impedance point P that occurs at the lowest frequency (6 GHz) at which the wavelength λ of the oscillation signal is the longest, so the high impedance range that is produced will be narrowest. Thus, with this embodiment, unnecessary radiation produced from the housing 22 can be effectively reduced.
Also, an example was given in this embodiment in which the high impedance range was contracted to just a single point (the high impedance point P), but the present invention is not limited to this, and can of course be similarly applied when the line length of the extension line L is set shorter the above-mentioned line length and the range is reduced to be smaller than the conventional high impedance range B shown in
Generalized Model of Reducing High Impedance Range
Next, using a generalized model to reduce the size of the conventional high impedance range B discussed above will be described.
In
If we let the coordinates of points A, B and C be (xa,ya)=(0,0), (xb,yb)=(0,1), and (xc,yc), we obtain the following equations.
nλ/4=√(xc2+yc2),mλ/4=√{xc2+(1−yc)2}
∴m2(xc2+yc2)=n2{xc2+(1−yc)2}
when m=n, yc=½
when m>n, xc2+{yc+n21/(m2−n2)}2=(nm1)2/(m2−n2)
Thus, when the wavelength λ is varied, the path of the points C becomes the center line of AB when m=n, and when m>n, the path scribes an arc with a center of (0, n21/(m2−n2)) and a radius of nm1/√(m2−n2).
Also, if we let the oscillation frequency be f1≤f≤f2, the wavelength λ=c/f falls within a range of λ2≤λ≤λ1 (the range drawn with a thick line in
If the high impedance range related to unnecessary radiation shown in
Here, since impedance can usually be kept low within a range of a distance of λ/20 from the grounding site, it is common for a plurality of grounding sites provided to a housing or substrate, particularly one with no limitations on cost or shape, to be designed at a spacing of λ/10 between them, and for the intermediate position between these grounding sites to be at a distance of exactly λ/20 from the grounding sites.
Because of this, with the present disclosure, if the spacing between two areas of high impedance can be kept within a width range of λ/10 (specific threshold), it will be possible for the overall area of high impedance to be limited to a narrow range. This will be described in detail through reference to
Variation in Distribution of High Impedance Range
In
In
In
In
In
As discussed above, to narrow a high impedance range, it is necessary at least for the spacing between two points of high impedance at the highest frequency f2 related to unnecessary radiation to be 1/10 the wavelength at that frequency (
In
A specific example of this is shown in
The length of the wiring pattern 20m is determined as follows. In this embodiment, since the wiring pattern 20m is disposed on the main board 20, the wavelength λ′ of the oscillation signal is shortened on the main board 20 by the dielectric constant er of the main board 20 to 1/(er1/2) the wavelength λ in a vacuum. For example, if the distance from the position of the high impedance point P of the housing 22 to the right corner 22s of the rear face d of the housing 22 is 90% of ¼ times the wavelength λ, then a distance of 10% of ¼ times the wavelength λ′ at the dielectric constant er should be used for the line length of the wiring pattern 20m. More specifically, if we let the dielectric constant er of the main board 20 be 4, and the oscillation frequency f of the oscillation signal be 6 GHz, then the wavelength λ′ at the dielectric constant er is as follows.
λ′=(1/(er1/2))λ=(½)×(c/f)
c: speed of light=(½)×(3×108/(6×109))=0.025 m=25.00 mm
Therefore, the line length can be calculated as 25.00×(¼)×0.1=0.625 mm≈0.6 mm
Therefore, in this embodiment, since the second grounding site 22w′ is disposed in a specific area of the main board under the housing 22, even if a microprocessor, a memory, or the like is disposed near the housing 22 on the outside, these devices will not get in the way, and the second grounding site 22w′ can be properly disposed at the accurate spacing of the length of the wiring pattern 20m from the housing 22.
Modification Example of Extension LineMore specifically, an extension line L5 is made up of a wiring pattern 20q that extends from the ungrounded land 20g toward a specific area of the main board 20 under the housing 22 as shown in
With the above embodiment and the first and second modification examples, since the extension lines L2 to L5 make use of wiring patterns formed on the main board 20, there is no need for other members such as metal wires, and the extension lines L to L5 can be simply configured.
Therefore, in this fourth modification example, the distance between the corner of the housing 22 (land 20g) and the grounding site 22w′ can be adjusted merely by adjusting the length of the wire-shaped conductor L6 and the wiring pattern 20q.
Therefore, in this modification example, the distance between the corner of the housing 22 (land 20g) and the grounding site 22w′ can be adjusted merely by adjusting the length of the leaf spring-shaped conductor L7.
In all of the modification examples of the extension line L described above, the length of the extension line L can be freely increased or decreased, so the distance from the high impedance point P of the housing 22 to the grounding site 22w can be accurately set to an odd-numbered multiple of ¼ the wavelength λ, regardless of the oscillation frequency range of the oscillation signal of the VCO/PLL circuit 3.
Eighth EmbodimentAn eighth embodiment of the present disclosure will now be described through reference to
As shown in
In this embodiment, in
Therefore, in this embodiment, the impedance at the high impedance point P generated in a developed view of the housing 22 can be lowered by the grounding site 22s. As a result, the unnecessary radiation from the high impedance point P produced by the two grounding sites (first specific first site (first site) and second specific first site (second site)) 22r and 22w can be effectively reduced by the above-mentioned other grounding site (second site (third site)) 22s.
Also, just as with the above embodiment, this embodiment is effective when the high impedance range spreads out somewhat.
Specifically, in
In this eighth embodiment, in addition to using the grounding site 22w to ground a position that is separated from the right corner of the rear face d of the housing 22 by the extension line L, in this modification example, the left corner 22r of the front face b and the land 22s provided to the bottom edge k of the left face e are also grounded by grounding sites 22j and 22z via extension lines R1 and R2, respectively.
In this modification example, even if the lowest frequency of the oscillation signal of the VCO/PLL circuit 3 is lower than 6 GHz, or if the size of the housing 22 is relatively small, etc., since the distances by which the three grounding sites 22j, 22w, and 22z are separated from the housing 22 can be freely adjusted, the impedance can be lowered at the high impedance point P more reliably and easily.
Ninth EmbodimentA ninth embodiment of the present disclosure will now be described through reference to
In the sixth embodiment above, a grounding site was disposed at a position of the housing 22 where only the high impedance point P was generated, but in this embodiment, a grounding site is further disposed at a position where the high impedance range is eliminated.
Specifically, in
With the above configuration, in this embodiment, the other end of the extension line R with a longer extension line is used as a grounding site 22x, and the distance M from this grounding site 22x to the high impedance point P can be a distance that exceeds one times ¼ the wavelength λ at the lowest frequency (6 GHz), so the generation of the high impedance point P can be eliminated, and no unnecessary radiation will occur anywhere in the housing 22.
Furthermore, when the distance M is an even-numbered multiple of ¼ the wavelength λ (such as ½), the impedance can be directly lowered at the high impedance point P.
Tenth EmbodimentAs shown in
With the above configuration, in this embodiment overlapping sites can be eliminated at distances of one and three times ¼ the wavelength λ of the oscillation signal of the VCO/PLL circuit 3 away from the grounding sites 22y and 22v.
Therefore, as shown in
Furthermore, in the front face b of the housing 22, a television broadcast signal cable 24 is connected to the F-type connector 23 attached to an attachment hole 23a, and the high impedance range E occurs in the upper middle part of the front face b of the housing in
Furthermore, in this embodiment, the high impedance range E that occurs near the F-type connector 23 was eliminated, but the present invention is not limited to this. For instance, even if a high impedance range occurs in the housing 22, the site where the high impedance range is generated should be at least a specific distance away from the F-type connector 23, to the extent that the unnecessary radiation produced from this high impedance range has either no effect or extremely little effect. Furthermore, when the distance from the grounding site 22y to the F-type connector 23 is an even-numbered multiple of ¼ the wavelength λ (such as ½), the impedance can be directly lowered near the F-type connector 23.
In the ninth and tenth embodiments above, only one of two corners was grounded via the extension line R or Y, but all of the grounded corners may, of course, be grounded via an extension line.
Eleventh EmbodimentAn eleventh embodiment of the present disclosure will now be described through reference to
In the sixth embodiment above (
More specifically, in this embodiment, in the developed view of the housing 22 in
In a developed view of the housing 22, the point P is the point nearest the right corner 22g of the rear face d among points of a distance that is three times ¼ the wavelength λ at the lowest frequency (in the drawing, 6 GHz) in the variable frequency range of the oscillation signal of the VCO/PLL circuit 3 from the left corner 22r of the front face b (points within the high impedance range B shown in
Therefore, in this embodiment, with a housing 22, using the grounding site of the left corner 22r of the front face b as a reference impedance, since the point P is the only area that is an odd-numbered multiple (three times) of λ/4 away from this grounding site in straight line distance in a developed view from this grounding site and at a distance that is an even-numbered multiple (two times) of ¼ the wavelength λ at the lowest frequency (6 GHz) of the oscillation signal away from the open site 22op of the housing 22 (the other end of the extension line L), the high impedance range generated becomes the narrowest. Thus, in this embodiment, the unnecessary radiation from the housing 22 can be effectively lowered.
If the extension line L is a point-to-point construction, there will be no reduction in wavelength tied to dielectric constant. Therefore, the actual line length of the extension line L may be used in calculating the distance to the high impedance point P.
The configuration in which the other end of the extension line L is open can be the configuration shown in
A configuration in which the other end of the extension line L is open can also be applied to the already discussed configurations in
Therefore, in this embodiment, the impedance is actively lowered at the point P that becomes a high impedance range by opening the other end of the extension line L, so the generation of unnecessary radiation can be eliminated even more.
Modification ExampleThus, when the distance from the high impedance point P to the open site 22op is an even-numbered multiple of ¼ the wavelength λ (such as ½), the high impedance range of the housing 22 can be limited to the point P, but the method discussed in the ninth embodiment can also be applied in this embodiment.
Specifically, when the distance from the high impedance point P to the open site 22op is an even-numbered multiple of ¼ the wavelength λ (such as ½), the high impedance point P can also be prevented from being generated. Furthermore, when the distance from the high impedance point P to the open site 22op is further extended to an odd-numbered multiple of ¼ the wavelength λ (such as ¾), the impedance can be directly lowered at the high impedance point P.
Also, in
In Developed View of the Housing 22
When Connection Between Side Faces is Weak
In the developed view of the housing 22 shown in
When Connection Between Side Faces is Strong
On the other hand, as shown in
For instance, in
In
Thus, when the connections between the side faces of the housing 22 are strong, the developed view has to be supplemented by taking into account all of the paths of strong electrical connections.
Other EmbodimentsIn the above description, the oscillation frequency range of the oscillation signal of the VCO/PLL circuit 3 was between 6 and 8 GHz, which is used for television broadcast reception, but the present invention is not limited to this, and another frequency range may be used instead.
Also, the circuit configuration of the tuner IC 10 was given as a specific example in
Furthermore, in the above description, a tuner device for television broadcast reception was used as an example of this tuner device, but the present invention can of course be similarly applied to a tuner device for recording and reproduction, etc.
As described above, the present disclosure is useful when applied to a tuner device such as one used for receiving television broadcasts or for recording and reproduction, because even if a range of high impedance is generated in a housing due to grounding when a housing that covers an oscillator disposed on a substrate is grounded to the substrate, since another grounding site or an open site that lowers the impedance in this high impedance range is disposed on the housing, unnecessary radiation from the housing can be effectively reduced.
As described above, with the present disclosure, when a housing that covers an oscillator disposed on a substrate is grounded by being connected to the substrate, the grounding site of the housing to the substrate is used as a reference impedance, and the grounding site is disposed at a position where the overlapping range of the portion of the housing of higher impedance than a specific impedance is narrowed or eliminated, so unnecessary radiation from the housing can be effectively reduced, which makes this invention useful for application to a tuner device used for television broadcast reception, recording and reproduction, etc.
With the present disclosure, a display device can be provided in which an oscillator is disposed on a substrate, and with which less unnecessary radiation is emitted from the conductive housing connected to the ground component of a substrate. Specifically, with the display device in accordance with the present disclosure, the housing 22 is connected to the first sites 22r and 22s of the ground component of the substrate, and to the second site 22w that is different from the first sites 22r and 22s. The first sites 22r and 22s and the second site 22W are such that the first area B of the housing 22 at which the impedance is higher than the first threshold due to the first site 22r and 22s is disposed at a position overlapping at least part of the second area of the housing 22 at which the impedance is lower than the second threshold due to the second site. Therefore, the first area B of the housing at which the impedance is higher is smaller, so the unnecessary radiation emitted from the housing is reduced.
Also, with the present disclosure, a display device can be provided in which an oscillator is disposed on a substrate, and with which unnecessary radiation that is generated from a conductive housing connected to the ground component of the substrate is reduced. Specifically, the housing is connected to the first specific first site (first site) and the second specific first site (second site) of the ground component. The first specific first site (first site) and the second specific first site (second site) are disposed at positions where the distance between two overlapping points in the first specific first area (first area) of the housing in which the impedance is higher than the first threshold due to the first specific first site (first site) and the second specific first area (second area) of the housing in which the impedance is higher than the first threshold due to the second specific first site (second site), is at or under the specific threshold (such as 1/10 the wavelength corresponding to the oscillation frequency of the oscillation signal of the oscillator).
[1] In view of the state of the known technology and in accordance with an aspect of the present invention, the display device of the present disclosure includes a signal processor, a display component, a substrate, and a conductive housing. The signal processor includes an oscillator that is configured to output oscillation signal. The signal processor is configured to process signal whose frequency is higher than a specific threshold. The display component is configured to display video. The substrate has a ground component. The signal processor is disposed on the substrate. The conductive housing is connected to a first site of the ground component and to a second site that is different from the first site. The first site and the second site are disposed at positions where a first area of the housing in which an impedance is higher than a first threshold due to the first site overlap at least part of a second area of the housing in which an impedance is lower than a second threshold due to the second site.
In view of the state of the known technology and in accordance with another aspect of the present invention, the display device of the present disclosure includes a signal processor, a display component, a substrate, and a conductive housing. The signal processor includes an oscillator that is configured to output oscillation signal. The signal processor is configured to process signal whose frequency is higher than a specific threshold. The display component is configured to display video. The substrate has a ground component and a first conductor. The signal processor is disposed on the substrate. The conductive housing is connected to a first site of the ground component and to a second site of the first conductor. The first site and the second site are disposed at positions where a first area of the housing in which an impedance is higher than a first threshold due to the first site overlap at least part of a second area of the housing in which an impedance is lower than a second threshold due to the second site.
With these display devices mentioned above, when the housing is connected to the first site of a ground component disposed at a corner of the housing, for example, all or part of the first area of the housing at which the impedance is higher due to the first site overlaps the second area of the housing at which the impedance is lower due to the second site, so there is less unnecessary radiation in the first area of the housing where the impedance is higher. Therefore, even if the length, width, or other dimensions of the housing exceed half the wavelength λ of the highest oscillation frequency of the oscillator (λ/2), all or part of the first area of the housing where the impedance is higher can be lowered in impedance by the second site, and unnecessary radiation can be effectively reduced.
Furthermore, there is no need to dispose numerous grounding sites evenly on the side of the interior of the housing as in the past, and the housing can be manufactured with a simple configuration and inexpensively.
[2] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the first area is an area in the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the first site.
With this display device, the impedance is higher in the first area that is an odd-numbered multiple of ¼ the wavelength of the oscillation signal away from the first site, but since the second area of lower impedance overlaps within this range, the first area can be reduced in size, and unnecessary radiation can be effectively reduced.
[3] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is located at the ground component. The second area is a position in the housing that is an even-numbered multiple of ¼ the wavelength of the oscillation signal away from the second site.
With this display device, since the second area connected to the ground component is at a position in the housing that is an even-numbered multiple of ¼ the wavelength of the oscillation signal away from the second site, the impedance can be effectively lowered in this second area. Therefore, the first area where the impedance is higher can be effectively reduced in size, and unnecessary radiation can be effectively reduced.
[4] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is located outside the ground component, and the second area is in a position in the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second area is in a position in the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
With this display device, since the second area of the housing that is connected to the first conductor is in a position of the housing that is an odd-numbered multiple of ¼ the wavelength of the oscillation signal away from the second site, the impedance of this second area can be effectively reduced. Therefore, the first area of the housing where the impedance is higher can be effectively reduced in size, and unnecessary radiation can be effectively reduced.
[5] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the housing is connected to a third site that is different form the first site of the ground component and the second site. The housing has a third area in which an impedance is higher than the first threshold due to the third site. The first area and the third area overlap at two points, and a distance X between the two points satisfies the following condition:
0<X≤λ/10, where λ represents a wavelength of the oscillation signal. The two points are located within a circle with a radius of λ/20, centered at a point in the second area of the housing
With this display device, since the distance X between the two points where the first area and the third area overlap satisfies the condition of 0<X≤λ/10, as long as all or part of the area between these two points is used as a second area where the impedance is lower, then the first area and the third area will both have lower impedance due to a single second site.
[6] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the housing has a rectangular upper part and side parts that extend from edges of the upper part and are perpendicular to the upper part. The first site is disposed on a side part extending from a short edge of the upper part. The second site is disposed on a side part extending from a long edge of the upper part.
[7] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the first area and the second area each include a plurality of areas.
[8] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the first site and the second site each include a plurality of sites. The number of sites of the second site is equal to or less than the number of sites of the first sites.
[9] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the first site includes at least two sites. The second site includes one second area overlapping at least two first areas.
With these display devices (according to items [8] and [9]), since the number of sites of the second site is limited to the same as or less than the number of sites of the first site, there is no need to evenly dispose numerous conductor posts that connect the housing and the ground of the substrate as in the past, and the housing can be manufactured with a simple configuration and inexpensively.
[10] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is disposed at a specific position on the substrate that is separated from the housing by an extension line connected to the housing.
With this display device, since the second site can be disposed at some position that is separated from the housing by an extension line extending from the housing, this affords greater latitude in the position of the second site that lowers the impedance of the high impedance range produced by the first site.
[11] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the housing is disposed in a specific area of the substrate. The second site is disposed in the specific area.
[12] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the extension line is a wire disposed on the substrate.
With these display devices (according to items [11] and [12]), since the extension line is disposed in a specific area of the substrate located below the housing, even if other constituent parts of the tuner device, such as a digital processing circuit or an audio circuit, is disposed near and to the side of the housing on the substrate, these devices will not get in the way, and the high impedance range can be easily lowered.
[13] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the first area or the second area includes an area according to a range of variation of a wavelength of the oscillation signal.
With this display device, even if the first area of higher impedance changes according to a wavelength change accompanying a change in the frequency of the oscillation signal of the oscillator, the second area where the impedance is low will also change, including the range of change thereof, so no matter at what oscillation frequency the oscillator oscillates, unnecessary radiation will always be effectively reduced everywhere on the housing.
[14] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the display device further includes a connector to which a signal cable is connected and that is provided to the housing. The first area is located near the connector.
With this display device, with a housing in which a television broadcast signal cable is connected to the connector, for example, even if the range near the connector is a first area of high impedance due to the first site, since the second site will lower the impedance of all or part of the first area in the second area, the impedance distribution over the housing will tend not to be affected by variance in the state (type, material, shape, etc.) of the signal cable, and it will be less likely that unnecessary radiation is produced by variance in the state of the signal cable.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the range of the oscillation frequency of the oscillation signal is at least 2 GHz.
With this display device, unnecessary radiation can be effectively reduced in a display device comprising a tuner device used for television broadcast reception.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the signal processor is a wireless communication component that sends and receives information signals or a tuner that receives broadcast signals.
[15] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the first site includes a first specific first site and a second specific first site. The first area includes a first specific first area in which an impedance is higher than the first threshold due to the first specific first site and a second specific first area in which an impedance is higher than the first threshold due to the second specific first site. The first specific first area and the second specific first area overlap at two overlapping points. The first specific first site and the second specific first site are disposed at positions where a distance between the two overlapping points of the first specific first area and the second specific first area is at or under a specific threshold.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is located at the ground component. The second area is located in an area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is located outside the ground component. The second area is located in an area of the housing that is an even-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
As described above, with the display device of the present disclosure, even if a range of high impedance occurs in a housing due to the grounding site, since a second site that forcibly changes this range to a lower impedance is disposed on the substrate, unnecessary radiation that is produced from the housing can be effectively reduced, and the number of grounding sites to the ground potential part of the substrate can be limited to a far smaller number than in the past, making it possible to manufacture the housing easily and inexpensively.
Also, to achieve the stated object, with the present disclosure, since unnecessary radiation is inevitably generated at parts of the housing where the impedance is high (using a grounding site of the housing as a reference impedance), so unnecessary radiation is reduced by a configuration in which these parts of the housing where the impedance is high are eliminated as much as possible.
[16] In view of the state of the known technology and in accordance with another aspect of the present invention, the display device of the present disclosure includes a signal processor, a display component, a substrate, and a conductive housing. The signal processor includes an oscillator that is configured to output oscillation signal. The signal processor is configured to process signal whose frequency is higher than a specific threshold. The display component is configured to display video. The substrate has a ground component. The signal processor is disposed on the substrate. The conductive housing is connected to a first site of the ground component and to a second site that is different from the first site. The first site and the second site are disposed at positions where a distance between two overlapping points in a first area of the housing in which an impedance is higher than a first threshold due to the first site and a second area of the housing in which an impedance is higher than the first threshold due to the second site, is at or under a specific threshold.
With this display device, since the first site and second site that are provided to the housing for making a ground connection are disposed at positions where the distance between two overlapping points in a first area and a second area in which the impedance is higher due to these two grounding sites, is at or under a specific threshold, the range of the first area and second area of high impedance can be kept overall within a narrow range of the housing area. Therefore, when the impedance is lowered in this narrow range of high impedance area, the impedance may be lowered in only this narrow range of area, which makes design easier.
[17] In accordance with a preferred embodiment according to the display device mentioned above, the first area is located in an area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the first site.
[18] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is located at the ground component. The second area is located in an area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
[19] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the second site is located outside the ground component. The second area is located in an area of the housing that is an even-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
With these display devices (according to items [17] to [19]), the first area and the second area are areas of higher impedance than other areas of the housing, but it is possible to limit these areas.
[20] In accordance with a preferred embodiment according to any one of the display devices mentioned above, the specific threshold is λ/10 where λ represents the wavelength of the oscillation signal.
With this display device, since the first site and the second site of the housing are disposed so that the distance between two overlapping points in the first area and the second area will be no more than λ/10 of the wavelength λ of the oscillation signal, it is possible to effectively limit all or part of the first area and second area.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the wavelength of the oscillation signal is the wavelength with the lowest frequency in the frequency variable range of the oscillator.
With this display device, even with the two high impedance areas located the farthest away from the first site and the second site, since the distance between two overlapping points in these two high impedance areas is at or under a specific threshold, these high impedance areas can be reliably limited.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the display device further includes an extension line that connects the housing and the first site. The first site is disposed at a position that is some distance from the housing.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the display device further includes an extension line that connects the housing and the second site. The second site is disposed at a position that is some distance from the housing.
With these display devices, since the first site and the second site are disposed at positions that are some distance from the housing, the distance between two overlapping points in the first area and the second area of the housing in which the impedance is high due to these first and second sites can be easily kept at or under a specific threshold.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the housing is disposed in a specific area of the substrate, and the second site is disposed in a specific area of the substrate.
With this display device, even when the second site is disposed at a position that is away from the housing, since the second site is disposed in a specific area of the substrate where the housing is disposed, even when other constituent parts of a tuner device, such as a digital processing circuit or an audio circuit, are disposed near and to the side of the housing on the substrate, these constituent parts will not get in the way, and the grounding site can be disposed at a position that is away from the housing.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the display device further includes a connector that is provided to the housing and is connected to a signal cable. The first area and the second area are located at sites that are at least a specific distance away from the connector.
With this display device, even if a television broadcast signal cable is connected to the connector, for example, since a first area and a second area of high impedance are located away from the connector, the impedance distribution over the housing will be less likely to be affected by variance in the state (type, material, shape, etc.) of the signal cable, and the occurrence of unnecessary radiation due to variance in the state of the signal cable can be suppressed.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the substrate has a third site. The third site is disposed so that a third area of the housing in which the impedance is lower than a specific threshold due to said third site overlaps the first area and/or the second area.
With this display device, since a third site is disposed on the substrate so that a third area of low impedance will overlap the first area and/or the second area of high impedance in the housing, unnecessary radiation from the first area or the second area can be effectively reduced.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the third site is connected to the ground component. The third area is located in an area of the housing that is an even-numbered multiple of ¼ the wavelength of the oscillation signal away from the third site.
With this display device, since the third site is connected to the ground component and the third area is located in an area that is an even-numbered multiple of ¼ the wavelength of the oscillation signal away from the third site, the first area or the second area in which the impedance is high can be reliably reduced to a low impedance by the third site, and the generation of unnecessary radiation from the first area or the second area can be effectively reduced.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the third site is not connected to the ground component. The third area is located in an area of the housing that is an odd-numbered multiple of ¼ the wavelength of the oscillation signal away from the third site.
With this display device, since the third site is not connected to the ground component and the third area is located in an area that is an odd-numbered multiple of ¼ the wavelength of the oscillation signal away from the third site, the first area or the second area in which the impedance is high can be reliably reduced to a low impedance by the third site, and the generation of unnecessary radiation from the first area or the second area can be effectively reduced.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the display device further includes an extension line that connects the housing and the third site. The third site is disposed at a position that is some distance from the housing.
With this display device, since the third site is disposed at a position that is some distance from the housing, this third site can reliably lower the impedance in the first area or the second area in which the impedance is high in the housing.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the housing is disposed in a specific area of the substrate. The third site is disposed in a specific area of the substrate.
With this display device, even though the third site is located at a position that is away from the housing, since the third site is disposed in a specific area of the substrate in which the housing is disposed, even when other constituent parts of a tuner device, such as a digital processing circuit or an audio circuit, are disposed near and to the side of the housing on the substrate, these constituent parts will not get in the way, and the grounding site can be disposed at a position that is away from the housing.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the range of the oscillation frequency of the oscillation signal is at least 2 GHz.
With this display device, unnecessary radiation can be effectively reduced in a tuner device used to receipt television broadcasts, including the VCO frequency range used for television broadcast reception.
In accordance with a preferred embodiment according to any one of the display devices mentioned above, the signal processor is a wireless communication component that sends and receives information signals, or a tuner that receives broadcast signals. As described above, with the tuner device of the present disclosure, the distance between two overlapping points in two areas of high impedance on a conductor path over which oscillation signals propagate through a housing is limited to be at or under a specific threshold, so the range in which unnecessary radiation occurs in the housing can be narrowed or eliminated, and unnecessary radiation can be effectively reduced.
In understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including”, “having” and their derivatives. Also, the terms “part,” “section,” “portion,” “member” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts unless otherwise stated.
The term “attached” or “attaching”, as used herein, encompasses configurations in which an element is directly secured to another element by affixing the element directly to the other element; configurations in which the element is indirectly secured to the other element by affixing the element to the intermediate member(s) which in turn are affixed to the other element; and configurations in which one element is integral with another element, i.e. one element is essentially part of the other element. This definition also applies to words of similar meaning, for example, “joined”, “connected”, “coupled”, “mounted”, “bonded”, “fixed” and their derivatives. Finally, terms of degree such as “substantially”, “about” and “approximately” as used herein mean an amount of deviation of the modified term such that the end result is not significantly changed.
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. For example, unless specifically stated otherwise, the size, shape, location or orientation of the various components can be changed as needed and/or desired so long as the changes do not substantially affect their intended function. Unless specifically stated otherwise, components that are shown directly connected or contacting each other can have intermediate structures disposed between them so long as the changes do not substantially affect their intended function. The functions of one element can be performed by two, and vice versa unless specifically stated otherwise. The structures and functions of one embodiment can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature which is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such feature(s). Thus, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
Claims
1. A display device comprising:
- a signal processor including an oscillator that outputs oscillation signal, the signal processor processing signal whose frequency is higher than a specific threshold;
- a display component that displays video;
- a substrate having a ground component, the signal processor being disposed on the substrate; and
- a conductive housing connected to a first site of the ground component and to a second site that is different from the first site,
- the first site and the second site being disposed at positions where a first area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the first site overlaps at least part of a second area of the housing that is a multiple of ¼ wavelength of the oscillation signal away from the second site.
2. The display device according to claim 1, wherein
- the second site is located at the ground component, and
- the second area is in a position in the housing that is an even-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
3. The display device according to claim 1, wherein
- the second site is located outside the ground component, and
- the second area is in a position in the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the second site.
4. The display device according to claim 1, wherein where λ represents a wavelength of the oscillation signal, and
- the housing is connected to a third site that is different form the first site of the ground component and the second site,
- the housing has a third area that overlaps with the first area at two points, with a distance X between the two points satisfying the following condition: 0<X≤λ/10
- the two points are located within a circle with a radius of λ/20, centered at a point in the second area of the housing.
5. The display device according to claim 1, wherein
- the housing has a rectangular upper part and side parts that extend from edges of the upper part and are perpendicular to the upper part,
- the first site is disposed on a side part extending from a short edge of the upper part, and
- the second site is disposed on a side part extending from a long edge of the upper part.
6. The display device according to claim 1, wherein
- the first area and the second area each include a plurality of areas.
7. The display device according to claim 1, wherein
- the first site and the second site each include a plurality of sites, and
- the number of sites of the second site is equal to or less than the number of sites of the first sites.
8. The display device according to claim 1, wherein
- the second site is disposed at a specific position on the substrate that is separated from the housing by an extension line connected to the housing.
9. The display device according to claim 8, wherein
- the housing is disposed in a specific area of the substrate, and
- the second site is disposed in the specific area.
10. The display device according to claim 9, wherein
- the extension line is a wire disposed on the substrate.
11. The display device according to claim 1, wherein
- the first area or the second area includes an area according to a range of variation of a wavelength of the oscillation signal.
12. The display device according to claim 1, further comprising
- a connector to which a signal cable is connected and that is provided to the housing,
- the first area being located near the connector.
13. The display device according to claim 1, wherein
- the first site includes a first specific first site and a second specific first site,
- the first area includes a first specific first area and a second specific first area that overlap at two overlapping points, and
- the first specific first site and the second specific first site are disposed at positions where a distance between the two overlapping points of the first specific first area and the second specific first area is at or under a specific threshold.
14. The display device according to claim 1, wherein
- the oscillation signal has an oscillation frequency of 6 to 8 GHz.
15. A display device comprising:
- a signal processor including an oscillator that outputs oscillation signal, the signal processor processing signal whose frequency is higher than a specific threshold;
- a display component that displays video;
- a substrate having a ground component, the signal processor being disposed on the substrate; and
- a conductive housing connected to a first site of the ground component and to a second site that is different from the first site,
- the first site and the second site being disposed at positions where a distance between two overlapping points in a first area of the housing that is an odd-numbered multiple of ¼ wavelength of the oscillation signal away from the first site and a second area of the housing that is a multiple of ¼ the wavelength of the oscillation signal away from the second site, is at or under a specific threshold.
16. The display device according to claim 15, wherein
- the second site is located at the ground component, and
- the second area is located in an area of the housing that is an odd-numbered multiple of ¼ the wavelength of the oscillation signal away from the second site.
17. The display device according to claim 15, wherein
- the second site is located outside the ground component, and
- the second area is located in an area of the housing that is an even-numbered multiple of ¼ the wavelength of the oscillation signal away from the second site.
18. The display device according to claim 15, wherein
- the specific threshold is λ/10 where λ represents the wavelength of the oscillation signal.
19. The display device according to claim 15, wherein
- the oscillation signal has an oscillation frequency of 6 to 8 GHz.
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Type: Grant
Filed: Jan 4, 2019
Date of Patent: Jun 9, 2020
Patent Publication Number: 20190141277
Assignee: FUNAI ELECTRIC CO., LTD. (Osaka)
Inventor: Shinichi Kodama (Osaka)
Primary Examiner: Robert J Pascal
Assistant Examiner: Kimberly E Glenn
Application Number: 16/239,987
International Classification: H04N 5/50 (20060101); H04B 15/06 (20060101); H05K 9/00 (20060101); H04N 5/655 (20060101); H03L 7/099 (20060101);